1. Field of the Invention
The present invention relates to a laser welding apparatus and a laser welding method, and more particularly, to a laser welding apparatus and a laser welding method which perform welding while supplying a shielding gas to a welded part.
2. Description of Related Art
Laser welding is a welding method in which welding is performed with a laser beam as a source of heat. In a case where two metal plates are stacked and welded, the two metal plates are superimposed one on the other and are then scanned with a laser beam. Accordingly, the part irradiated with the laser beam is heated, so that the two metal plates are melted. Melts of the two metal plates are mixed and then solidified, thereby joining the two metal plates in a stacked state. At this time, the cross-sectional shape of a bead to be formed varies depending on the shielding gas supplied to the welded part.
Japanese Unexamined Patent Application Publication No. 2004-130360 discloses a technique relating to a laser welding apparatus which uses a mixed gas of inert gas and oxygen gas as a shielding gas.